Well,other thah the ovbious size differences in the 2,the bare facts are as follows.
The 602 will manage about 3 to 5 mpg average empty,the multi will usually make 8 to 10 depending on the fuel used.
The 5 ton has power steering,the deuce does not.
5 tons have a better braking system in my opinion,same design just larger shoes/drums.
The 602 has about 2 times the torque of the LDT multifuel,about 100 more HP.
The 5 ton has a direct 5th gear trans,the multi has a 5th gear OD trans.
If you go by what the data plate says,the deuce will top out at 56 mph,the 5 ton at 60 mph.
Everything drivetrain related will weigh about twice as much on the 5 ton vs the deuce.
Plan on about 15 gallons of 90W for a complete drivetrain oil change(diffs,trans,t- case)in the 5 ton.
Fuel tank holds 78 gal vs 50 for the deuce.
Depending on your state laws,you may need a CDL for the 5 ton.
The 602 is a good engine,but parts are getting harder to find(manifolds,exhaust,gasket sets).
The usual tune ups are required every now and then(plugs,points,wires,cap,rotor,coil) on the 6602.
The 602 has 100.3333333 ci per cylinder,the multi has 79.66666666 ci per cylinder.
The 602 also has a special pulley for the alternator/generator,don't lose it!!
People following the 5 ton with the 602 will have to stop every now and then to let thier eyes quit watering and catch their breath,that beast throws out some mean fumes!!
That's about all I can think of right now.